Description of Prior Art
Sod mats have long been used in the landscaping industry. Reinforced flower and groundcover sod mats were tested in the 1970's. These sod mats have serious commercial limitations for the grower, landscaper, or consumer. Some also have environmental limitations.
Many flower and grass sod mats contain ungerminated seeds. Germination and early seedling growth requires adequate rainfall and good soil temperature. In addition, the type of soil is often problematic. Also, many of these seed sod mats require complex, expensive, and specialized equipment which makes producing small custom lots difficult and expensive for small landscape jobs. Many of these use moisture sensitive glues or other ingredients which may lead to storage or shipping instabilities or even premature germination. In addition, some are based on a synthetic hydrophobic polymer which then needs hydrophilic materials added to encourage germination and good growth. These hydrophilic materials are often superabsorbent hydrogels which are expensive to produce and to use.
Flower and sod mats grown on a very open plastic netting for sod reinforcement are difficult to completely cover with thin planting mediums, use significant synthetic material per square meter, and often have delayed harvest times due to the open structure. Plastic netting which is less open often damages the seedling roots by girdling them.
Flower sod mats grown on REEMAY.RTM. polyester spunbond fabrics are limited because the polyester is neither ultraviolet light degradable nor biodegradable, synthetic plastic consumption per square acre is often higher than needed, and only a limited range of strengths are suitable for good commercial sod mat production. Very low weight polyester spunbond fabrics are not generally commercially available. Higher polyester spunbond fabric weights and strengths retard seedling root penetration. For these reasons, the type of planting medium, planting medium weight, and planting depth are limited for best commercial production. Polyester spunbond fabrics are also moderately expensive.
It is often convenient to subdivide sod mats by hand in the field prior to installation. Some reinforced sod mats, even in light weights, have structures which when torn, also cause significant tearing of the plant root structure. Some other sod mats containing higher strength sod mat reinforcements are difficult to cut even with a knife.
In addition, many of these seed and sod mats axe designed to use only first quality grade products to produce seed or sod mats for the landscaper and consumer. This requires the use of more expensive ingredients and in general, increases the general cost to society of these sod mats.
Thus, sod mats heretofore known suffer from a number of disadvantages:
a) Their manufacture requires expensive, complex equipment. Often this equipment by its nature prevents optimum flower or groundcover production for small landscapers and/or customers.
b) Sod mats containing seeds only prevent economical production of sod mats of many herb, vegetable, flower, and groundcover species which are better propagated by cuttings, plant plugs, seedlings or plant divisions and the like.
c) Sod mats limited to seeds require control of environmental conditions such as moisture for the best germination. This leads to extra dollar, time and convenience expense for the landscaper or customer (if water is available).
d) Many sod mats are sensitive to moisture and humidity and may prematurely delaminate, decompose, germinate, or fall victim to fungus, diseases, or insects.
e) Sod mats and seed mats often contain more synthetic plastic than necessary for reinforcement of the specific flower sod because of limitations in availability of the reinforcement. Others use multiple layers of synthetic materials or other synthetic additives such as hydrogels.
f) Some sod mat reinforcements can only be used in lower strength ranges for good production of seed mats. This limits the species of plant materials which can be economically grown and the general applicability of the resulting sod mat.
g) Some sod mats are difficult to divide by hand, while others contain reinforcements with enough strength to damage sensitive roots during this subdivision process.
h) Current commercial REEMAY.RTM. polyester sod mat reinforcement will not decompose if exposed to sunlight due to heavy traffic or rain fall and the like, forcing the contractor and/or customer to cut away and clean up the unsightly portions if this occurs.
i) Many seed and sod mats are specifically engineered in a way that requires first quality sod mat reinforcements and thus cannot easily use second quality waste products to reduce the cost to society (and the consumer).
j) Traditional vegetable, herb, groundcover, and bedding plants are sold in pots and flats, which consume valuable natural resources for packaging and further add to society's refuse problem.
k) Traditional plant pots and flats are required by the grower in many styles and sizes for herbs, vegetables, flowers, and groundcovers at considerable expense to the grower for inventory, storage, handling, and disposal costs.
l) Some sod mat reinforcements are more expensive because of the type of synthetic resin used.